Mixed content in DTDs

GrantRobertson · November 2nd, 2009, 12:40 AM

On page 109 the book discusses declaring mixed content DTDs. The example given

Code:

<!ELEMENT description (#PCDATA | em | strong | br)*>

seems to create a situation where a description can contain text, em, strong, or br tags but that none of those tags can contain anything within them but text. Only after reading a lot more of the book (and I have also read many other XML books) was I finally able to figure out that those other elements (em, strong, br) all also have to be declared to indicate what elements they are allowed to contain. For instance :

Code:

<!ELEMENT em (#PCDATA | strong | br)*>
<!ELEMENT strong (#PCDATA | em | br)*>
<!ELEMENT br EMPTY>

If the authors would mention this I think it would make the whole concept much more clear.

Thanks.